1. Field of the Invention
The present invention generally relates to an optical waveguide holding member to be mounted on a printed circuit board of an optical transceiver and the optical transceiver using the optical waveguide holding member. The optical transceiver receives an optical signal from an external device and converts the received optical signal into an electric signal, and transmits another optical signal to the external device by converting another electric signal into the other optical signal.
2. Description of the Related Art
Communications by using optical fibers have progressed with the development of a large capacity communication network at high speed operations and the development of advanced communication control devices. For example, in a communication terminal (personal computer and peripheral) in an office or a personal house, when signals are transmitted and received by connecting the communication terminal to a communication network such as the Internet, an optical fiber has been used between the communication terminal and the communication network. An optical transceiver receives an optical signal from an external device and converts the received optical signal into an electric signal, and transmits another optical signal to the external device by converting another electric signal into the other optical signal. The optical transceiver is used for connecting the communication terminal to the optical fiber by providing an optical waveguide formed between the external optical fibers and photoelectric conversion elements of the optical transceiver (refer to Patent Document 1).
[Patent Document 1] Japanese Laid-Open Patent Application No. 2001-051271
In the optical transceiver, an optical waveguide holding member for holding an optical waveguide is disposed on a printed circuit board on which the photoelectric conversion elements are mounted. Generally, the printed circuit board is formed of glass epoxy resin, and the optical waveguide holding member is formed of olefin based resin so as to have a function of cladding material. When the photoelectric conversion elements mounted on the printed circuit board are connected to the optical waveguide disposed on the optical waveguide holding member, light receiving and emitting sections of the photoelectric conversion elements face the corresponding ends of the optical waveguide, and optical centers of the light receiving and emitting sections are matched to corresponding optical centers of the ends. The positional accuracy between the optical centers must be ± a few μm.
The temperature of the optical transceiver rises to approximately 80 to 90° C. while the optical transceiver is used. The thermal expansion coefficients of the printed circuit board and the optical waveguide holding member are different. Consequently, due to a temperature change, the position where the optical waveguide holding member is connected to the printed circuit board may be shifted, and the optical centers of the light receiving and emitting sections of the photoelectric conversion elements and the optical centers of the ends of the optical waveguide may be shifted. When the optical centers are shifted by over some μm due to the thermal expansion difference in an environment where the temperature changes, the performance of the optical transceiver may be degraded.